Isichazi sefayela 2 simele iphutha elijwayelekile. (ezinye izincazelo zefayela ezikhethekile zifaka u-0 okokufaka okujwayelekile kanye no-1 kokuphumayo okujwayelekile). 2> /dev/null kusho ukuqondisa kabusha iphutha elijwayelekile ku/dev/null. /dev/null iyithuluzi elikhethekile elilahla yonke into ebhalwe kuyo.
Ithini incazelo ye-2 >&1?
I-&1 isetshenziselwa ukubhekisela kwinani lesichazi sefayela 1 (stdout). Manje ephuzwini 2>&1 kusho ukuthi “Qondisa kabusha i-stderr endaweni efanayo lapho siqondisa kabusha i-stdout”
Iyini i-$$ ku-Linux?
$$ ngu i-ID yenqubo (PID) yombhalo ngokwawo. I-$BASHPID i-ID yenqubo yesehlakalo samanje se-Bash. Lokhu akufani nokuguquguquka kwe-$$, kodwa ngokuvamile kunikeza umphumela ofanayo.
Kuyini u-2 ku-bash script?
Isichazi sefayela 1 sithi stdout futhi Isichazi sefayela 2 sithi stderr . Ukusebenzisa > ukuqondisa kabusha okukhiphayo kuyafana nokusebenzisa 1> .
Iyini i-$2 kuskripthi segobolondo?
$0 igama lombhalo ngokwawo (script.sh) $1 impikiswano yokuqala (igama lefayela1) $2 ngu- impikiswano yesibili (dir1) $9 ingxabano yesishiyagalolunye.
Kusho ukuthini ukuthi 1 kumyalezo wombhalo?
1 lisho ukuthi “Partner. "
Ithini incazelo ka-1 ngo-4?
Ingxenyana yokuqala-kwesine, ebhalwe ngezimpawu njenge-1/4, isho ukuthi “ucezu olulodwa, lapho kuthatha izingcezu ezine ukwenza yonke.” Ingxenyana eyodwa kwezine, ebhalwe ngezimpawu ezithi 1/4, isho “ucezu olulodwa, lapho kudingeka khona izingcezu ezi-4 ukwenza yonke.”
Liyini igobolondo le-$0?
$0 Inweba egameni legobolondo noma iskripthi segobolondo. Lokhu isethwe ekuqalisweni kwegobolondo. Uma i-Bash icelwa ngefayela lemiyalo (bona Isigaba 3.8 [Izikripthi Zeshell], ikhasi 39), i-$0 isethwe egameni lalelo fayela.
Kuthiwani uma ku-bash script?
Ekubhalweni kwe-bash, njengasemhlabeni wangempela, 'uma' isetshenziselwa ukubuza umbuzo. Umyalo othi 'uma' uzobuyisela impendulo yesitayela ethi yebo noma cha futhi ungakwazi ukubhala impendulo efanele.
Usho ukuthini u-2 kutheminali?
38. Incazelo yefayela 2 imele iphutha elijwayelekile. (ezinye izincazelo zefayela ezikhethekile zifaka u-0 okokufaka okujwayelekile kanye no-1 kokuphumayo okujwayelekile). 2> /dev/null kusho ukuqondisa kabusha iphutha elijwayelekile ku/dev/null. /dev/null iyithuluzi elikhethekile elilahla yonke into ebhalwe kuyo.
Kungani sisebenzisa 2 >> ukuqondisa kabusha?
Ungasebenzisa i-&[FILE_DESCRIPTOR] ukuze ubhekisele ivelu lesichazi sefayela; Isebenzisa 2>&1 izoqondisa kabusha i-stderr kunoma yiliphi inani elibekwe ku-stdout (futhi i-1>&2 izokwenza okuphambene).
Ngiyiqondisa kanjani kabusha i-stderr?
Ukuqondisa kabusha i-stderr, unezinketho ezimbalwa:
- Qondisa kabusha i-stdout kufayela elilodwa bese u-stderr uye kwelinye ifayela: umyalo> ukuphuma 2>iphutha.
- Qondisa kabusha i-stdout kufayela ( >out ), bese uqondisa kabusha i-stderr ku-stdout ( 2>&1 ): umyalo > ukuphuma 2>&1.